Several vehicle safety systems have been proposed that provide passenger safety in the event of a vehicular collision. Some vehicle safety systems also provide pedestrian safety in the event that a vehicle and a pedestrian impact each other.
For instance, some systems have been proposed that reduce the degree of pedestrian injury that impacts a vehicle hood during collision with a vehicle. Several of these systems decrease the force with which the pedestrian impacts the hood to thereby reduce the degree of injury. Also, several of these systems employ some sort of detection system that detects collision with a pedestrian and the like.
For example, JP-2005-538881A (PCT international publication) discloses such a system. Specifically, JP-2005-538881A discloses a system with a vehicle front contact sensor with at least one cavity. A sensing element is disposed in the cavity to detect a collision based on deformation of the cavity.
Also, JP-2005-538881 A discloses a technology of incorporating another sensor which can detect a pedestrian collision. In other words, the vehicle front contact sensor disclosed in JP-2005-538881A is not intended for detecting collision with a pedestrian.
FIG. 21 illustrates a bumper corresponding to the device and detecting method disclosed in JP-2005-538881A. As shown, the bumper includes a chamber member 2 with an air-tight chamber space defined therein, and which corresponds to the cavity in JP-2005-538881A. The chamber member 2 is included between a bumper reinforcement 1, which is fixed to side members Fm, and a bumper cover 4, which forms an outer-peripheral face of the bumper of the vehicle. Collision is detected by a pressure fluctuation in the space.
As shown, the front surface of the chamber member 2 and the bumper cover 4 is curved at each end. As such, the thickness of the chamber member in the forward and aft directions of the vehicle changes across the width of the chamber member 2. Thus, a deforming amount of the chamber member 2 can vary for the same collision conditions depending on the collision location as shown by comparing FIGS. 22 and 23. More specifically, because the thickness of the chamber member is relatively large near the middle of the bumper, a collision at the middle of the bumper is able to crush in a relatively large distance S1. In comparison, the same collision condition at the end of the bumper is only able to crush in a relatively small distance S2. Thus, the change of volume within the chamber space due to the collision also varies depending on the location of the collision. Therefore, the pressure-change detected by the collision detector likewise varies, which detrimentally affects the accuracy of the collision detector.
Furthermore, the collision detector described above may detect a collision, but the collision detector is unlikely to be able to distinguish between the objects with which the vehicle impacts. Accordingly, the collision detector is unlikely to be able to detect whether the vehicle has impacted a human body or not.
In view of the above, there exists a need for a collision detector which overcomes the above mentioned problems in the conventional art. The present disclosure addresses this need in the conventional art as well as other needs, which will become apparent to those skilled in the art.